10 replies to this topic

[Omar (OZ)]

I want to turn on a 12V dc fan (old cpu fan) when I press the button. Now I know the button side but where do I connect the wires? I know its a really simple thing but, I love this too much to experiment NOTE: The fan has 3 wires, Red, Black, Yellow... I do not know what the yellow one is for

[Steven Behnke]

I want to turn on a 12V dc fan (old cpu fan) when I press the button. Now I know the button side but where do I connect the wires? I know its a really simple thing but, I love this too much to experiment

NOTE: The fan has 3 wires, Red, Black, Yellow... I do not know what the yellow one is for

Yellow is most likely a temperature input to control the cpu fan's speed.

[Omar (OZ)]

Yellow is most likely a temperature input to control the cpu fan's speed.

do you know where the other two would go if I wanted to make the fan go on when I tell it to?

[RedHermit]

For controlling a 12v device, you will need a relay. I'm in the process of learning electronics myself, so I won't give you details (I don't want to miss something and have your nice Netduino die on you) - but here are some handy links to help you get started; http://www.sparkfun....utorials_id=119 http://www.glacialwa...byrobotics/?p=9 They're talking more about a relay control to a 120VAC source, but the principal is the same, you just have to find the correctly rated relay, transitor, diode, etc.. to breadboard it out.

[Omar (OZ)]

For controlling a 12v device, you will need a relay. I'm in the process of learning electronics myself, so I won't give you details (I don't want to miss something and have your nice Netduino die on you) - but here are some handy links to help you get started;

http://www.sparkfun....utorials_id=119
http://www.glacialwa...byrobotics/?p=9

They're talking more about a relay control to a 120VAC source, but the principal is the same, you just have to find the correctly rated relay, transitor, diode, etc.. to breadboard it out.

well It runs on 5V good, and I have some other things like little motors and smaller fans. I just don't understand how I would switch it on when I press the button,

[Chris Seto]

Yellow is most likely a temperature input to control the cpu fan's speed.

Yellow is actually TACH. It's for measuring the fan's speed.

[Steven Behnke]

Yellow is actually TACH. It's for measuring the fan's speed.

Ah, thanks. That's what I get for guessing.

[Omar (OZ)]

Yellow is actually TACH. It's for measuring the fan's speed.

do you know where the other two would go if I wanted to make the fan go on when I tell it to? like when I press the button

[dab]

Yep, generally PC fans are available in the following flavors:

2 wires: Constant speed
3 wires: Constant speed w/ tachometer output
4 wires: Variable speed w/ tachometer output and speed input (PWM)

I recently saw an article on the Make: blog where a guy had connected a 3-wire fan to an Arduino and it displayed the fan's speed on 7-segment displays. I think that would be a good re-make with the Netduino.

http://blog.makezine...th_arduino.html

[Omar (OZ)]

Yep, generally PC fans are available in the following flavors:

2 wires: Constant speed
3 wires: Constant speed w/ tachometer output
4 wires: Variable speed w/ tachometer output and speed input (PWM)

I recently saw an article on the Make: blog where a guy had connected a 3-wire fan to an Arduino and it displayed the fan's speed on 7-segment displays. I think that would be a good re-make with the Netduino.

http://blog.makezine...th_arduino.html

in that example as soon as the fan is in it starts up, what if I don't want that to happen? Does anyone know?

[Omar (OZ)]

Alright so relay it is. thanks guys